xref: /linux/fs/ubifs/sb.c (revision b8bb76713ec50df2f11efee386e16f93d51e1076)
1 /*
2  * This file is part of UBIFS.
3  *
4  * Copyright (C) 2006-2008 Nokia Corporation.
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of the GNU General Public License version 2 as published by
8  * the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it will be useful, but WITHOUT
11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
13  * more details.
14  *
15  * You should have received a copy of the GNU General Public License along with
16  * this program; if not, write to the Free Software Foundation, Inc., 51
17  * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18  *
19  * Authors: Artem Bityutskiy (Битюцкий Артём)
20  *          Adrian Hunter
21  */
22 
23 /*
24  * This file implements UBIFS superblock. The superblock is stored at the first
25  * LEB of the volume and is never changed by UBIFS. Only user-space tools may
26  * change it. The superblock node mostly contains geometry information.
27  */
28 
29 #include "ubifs.h"
30 #include <linux/random.h>
31 #include <linux/math64.h>
32 
33 /*
34  * Default journal size in logical eraseblocks as a percent of total
35  * flash size.
36  */
37 #define DEFAULT_JNL_PERCENT 5
38 
39 /* Default maximum journal size in bytes */
40 #define DEFAULT_MAX_JNL (32*1024*1024)
41 
42 /* Default indexing tree fanout */
43 #define DEFAULT_FANOUT 8
44 
45 /* Default number of data journal heads */
46 #define DEFAULT_JHEADS_CNT 1
47 
48 /* Default positions of different LEBs in the main area */
49 #define DEFAULT_IDX_LEB  0
50 #define DEFAULT_DATA_LEB 1
51 #define DEFAULT_GC_LEB   2
52 
53 /* Default number of LEB numbers in LPT's save table */
54 #define DEFAULT_LSAVE_CNT 256
55 
56 /* Default reserved pool size as a percent of maximum free space */
57 #define DEFAULT_RP_PERCENT 5
58 
59 /* The default maximum size of reserved pool in bytes */
60 #define DEFAULT_MAX_RP_SIZE (5*1024*1024)
61 
62 /* Default time granularity in nanoseconds */
63 #define DEFAULT_TIME_GRAN 1000000000
64 
65 /**
66  * create_default_filesystem - format empty UBI volume.
67  * @c: UBIFS file-system description object
68  *
69  * This function creates default empty file-system. Returns zero in case of
70  * success and a negative error code in case of failure.
71  */
72 static int create_default_filesystem(struct ubifs_info *c)
73 {
74 	struct ubifs_sb_node *sup;
75 	struct ubifs_mst_node *mst;
76 	struct ubifs_idx_node *idx;
77 	struct ubifs_branch *br;
78 	struct ubifs_ino_node *ino;
79 	struct ubifs_cs_node *cs;
80 	union ubifs_key key;
81 	int err, tmp, jnl_lebs, log_lebs, max_buds, main_lebs, main_first;
82 	int lpt_lebs, lpt_first, orph_lebs, big_lpt, ino_waste, sup_flags = 0;
83 	int min_leb_cnt = UBIFS_MIN_LEB_CNT;
84 	long long tmp64, main_bytes;
85 	__le64 tmp_le64;
86 
87 	/* Some functions called from here depend on the @c->key_len filed */
88 	c->key_len = UBIFS_SK_LEN;
89 
90 	/*
91 	 * First of all, we have to calculate default file-system geometry -
92 	 * log size, journal size, etc.
93 	 */
94 	if (c->leb_cnt < 0x7FFFFFFF / DEFAULT_JNL_PERCENT)
95 		/* We can first multiply then divide and have no overflow */
96 		jnl_lebs = c->leb_cnt * DEFAULT_JNL_PERCENT / 100;
97 	else
98 		jnl_lebs = (c->leb_cnt / 100) * DEFAULT_JNL_PERCENT;
99 
100 	if (jnl_lebs < UBIFS_MIN_JNL_LEBS)
101 		jnl_lebs = UBIFS_MIN_JNL_LEBS;
102 	if (jnl_lebs * c->leb_size > DEFAULT_MAX_JNL)
103 		jnl_lebs = DEFAULT_MAX_JNL / c->leb_size;
104 
105 	/*
106 	 * The log should be large enough to fit reference nodes for all bud
107 	 * LEBs. Because buds do not have to start from the beginning of LEBs
108 	 * (half of the LEB may contain committed data), the log should
109 	 * generally be larger, make it twice as large.
110 	 */
111 	tmp = 2 * (c->ref_node_alsz * jnl_lebs) + c->leb_size - 1;
112 	log_lebs = tmp / c->leb_size;
113 	/* Plus one LEB reserved for commit */
114 	log_lebs += 1;
115 	if (c->leb_cnt - min_leb_cnt > 8) {
116 		/* And some extra space to allow writes while committing */
117 		log_lebs += 1;
118 		min_leb_cnt += 1;
119 	}
120 
121 	max_buds = jnl_lebs - log_lebs;
122 	if (max_buds < UBIFS_MIN_BUD_LEBS)
123 		max_buds = UBIFS_MIN_BUD_LEBS;
124 
125 	/*
126 	 * Orphan nodes are stored in a separate area. One node can store a lot
127 	 * of orphan inode numbers, but when new orphan comes we just add a new
128 	 * orphan node. At some point the nodes are consolidated into one
129 	 * orphan node.
130 	 */
131 	orph_lebs = UBIFS_MIN_ORPH_LEBS;
132 #ifdef CONFIG_UBIFS_FS_DEBUG
133 	if (c->leb_cnt - min_leb_cnt > 1)
134 		/*
135 		 * For debugging purposes it is better to have at least 2
136 		 * orphan LEBs, because the orphan subsystem would need to do
137 		 * consolidations and would be stressed more.
138 		 */
139 		orph_lebs += 1;
140 #endif
141 
142 	main_lebs = c->leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS - log_lebs;
143 	main_lebs -= orph_lebs;
144 
145 	lpt_first = UBIFS_LOG_LNUM + log_lebs;
146 	c->lsave_cnt = DEFAULT_LSAVE_CNT;
147 	c->max_leb_cnt = c->leb_cnt;
148 	err = ubifs_create_dflt_lpt(c, &main_lebs, lpt_first, &lpt_lebs,
149 				    &big_lpt);
150 	if (err)
151 		return err;
152 
153 	dbg_gen("LEB Properties Tree created (LEBs %d-%d)", lpt_first,
154 		lpt_first + lpt_lebs - 1);
155 
156 	main_first = c->leb_cnt - main_lebs;
157 
158 	/* Create default superblock */
159 	tmp = ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size);
160 	sup = kzalloc(tmp, GFP_KERNEL);
161 	if (!sup)
162 		return -ENOMEM;
163 
164 	tmp64 = (long long)max_buds * c->leb_size;
165 	if (big_lpt)
166 		sup_flags |= UBIFS_FLG_BIGLPT;
167 
168 	sup->ch.node_type  = UBIFS_SB_NODE;
169 	sup->key_hash      = UBIFS_KEY_HASH_R5;
170 	sup->flags         = cpu_to_le32(sup_flags);
171 	sup->min_io_size   = cpu_to_le32(c->min_io_size);
172 	sup->leb_size      = cpu_to_le32(c->leb_size);
173 	sup->leb_cnt       = cpu_to_le32(c->leb_cnt);
174 	sup->max_leb_cnt   = cpu_to_le32(c->max_leb_cnt);
175 	sup->max_bud_bytes = cpu_to_le64(tmp64);
176 	sup->log_lebs      = cpu_to_le32(log_lebs);
177 	sup->lpt_lebs      = cpu_to_le32(lpt_lebs);
178 	sup->orph_lebs     = cpu_to_le32(orph_lebs);
179 	sup->jhead_cnt     = cpu_to_le32(DEFAULT_JHEADS_CNT);
180 	sup->fanout        = cpu_to_le32(DEFAULT_FANOUT);
181 	sup->lsave_cnt     = cpu_to_le32(c->lsave_cnt);
182 	sup->fmt_version   = cpu_to_le32(UBIFS_FORMAT_VERSION);
183 	sup->time_gran     = cpu_to_le32(DEFAULT_TIME_GRAN);
184 	if (c->mount_opts.override_compr)
185 		sup->default_compr = cpu_to_le16(c->mount_opts.compr_type);
186 	else
187 		sup->default_compr = cpu_to_le16(UBIFS_COMPR_LZO);
188 
189 	generate_random_uuid(sup->uuid);
190 
191 	main_bytes = (long long)main_lebs * c->leb_size;
192 	tmp64 = div_u64(main_bytes * DEFAULT_RP_PERCENT, 100);
193 	if (tmp64 > DEFAULT_MAX_RP_SIZE)
194 		tmp64 = DEFAULT_MAX_RP_SIZE;
195 	sup->rp_size = cpu_to_le64(tmp64);
196 
197 	err = ubifs_write_node(c, sup, UBIFS_SB_NODE_SZ, 0, 0, UBI_LONGTERM);
198 	kfree(sup);
199 	if (err)
200 		return err;
201 
202 	dbg_gen("default superblock created at LEB 0:0");
203 
204 	/* Create default master node */
205 	mst = kzalloc(c->mst_node_alsz, GFP_KERNEL);
206 	if (!mst)
207 		return -ENOMEM;
208 
209 	mst->ch.node_type = UBIFS_MST_NODE;
210 	mst->log_lnum     = cpu_to_le32(UBIFS_LOG_LNUM);
211 	mst->highest_inum = cpu_to_le64(UBIFS_FIRST_INO);
212 	mst->cmt_no       = 0;
213 	mst->root_lnum    = cpu_to_le32(main_first + DEFAULT_IDX_LEB);
214 	mst->root_offs    = 0;
215 	tmp = ubifs_idx_node_sz(c, 1);
216 	mst->root_len     = cpu_to_le32(tmp);
217 	mst->gc_lnum      = cpu_to_le32(main_first + DEFAULT_GC_LEB);
218 	mst->ihead_lnum   = cpu_to_le32(main_first + DEFAULT_IDX_LEB);
219 	mst->ihead_offs   = cpu_to_le32(ALIGN(tmp, c->min_io_size));
220 	mst->index_size   = cpu_to_le64(ALIGN(tmp, 8));
221 	mst->lpt_lnum     = cpu_to_le32(c->lpt_lnum);
222 	mst->lpt_offs     = cpu_to_le32(c->lpt_offs);
223 	mst->nhead_lnum   = cpu_to_le32(c->nhead_lnum);
224 	mst->nhead_offs   = cpu_to_le32(c->nhead_offs);
225 	mst->ltab_lnum    = cpu_to_le32(c->ltab_lnum);
226 	mst->ltab_offs    = cpu_to_le32(c->ltab_offs);
227 	mst->lsave_lnum   = cpu_to_le32(c->lsave_lnum);
228 	mst->lsave_offs   = cpu_to_le32(c->lsave_offs);
229 	mst->lscan_lnum   = cpu_to_le32(main_first);
230 	mst->empty_lebs   = cpu_to_le32(main_lebs - 2);
231 	mst->idx_lebs     = cpu_to_le32(1);
232 	mst->leb_cnt      = cpu_to_le32(c->leb_cnt);
233 
234 	/* Calculate lprops statistics */
235 	tmp64 = main_bytes;
236 	tmp64 -= ALIGN(ubifs_idx_node_sz(c, 1), c->min_io_size);
237 	tmp64 -= ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size);
238 	mst->total_free = cpu_to_le64(tmp64);
239 
240 	tmp64 = ALIGN(ubifs_idx_node_sz(c, 1), c->min_io_size);
241 	ino_waste = ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size) -
242 			  UBIFS_INO_NODE_SZ;
243 	tmp64 += ino_waste;
244 	tmp64 -= ALIGN(ubifs_idx_node_sz(c, 1), 8);
245 	mst->total_dirty = cpu_to_le64(tmp64);
246 
247 	/*  The indexing LEB does not contribute to dark space */
248 	tmp64 = (c->main_lebs - 1) * c->dark_wm;
249 	mst->total_dark = cpu_to_le64(tmp64);
250 
251 	mst->total_used = cpu_to_le64(UBIFS_INO_NODE_SZ);
252 
253 	err = ubifs_write_node(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM, 0,
254 			       UBI_UNKNOWN);
255 	if (err) {
256 		kfree(mst);
257 		return err;
258 	}
259 	err = ubifs_write_node(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM + 1, 0,
260 			       UBI_UNKNOWN);
261 	kfree(mst);
262 	if (err)
263 		return err;
264 
265 	dbg_gen("default master node created at LEB %d:0", UBIFS_MST_LNUM);
266 
267 	/* Create the root indexing node */
268 	tmp = ubifs_idx_node_sz(c, 1);
269 	idx = kzalloc(ALIGN(tmp, c->min_io_size), GFP_KERNEL);
270 	if (!idx)
271 		return -ENOMEM;
272 
273 	c->key_fmt = UBIFS_SIMPLE_KEY_FMT;
274 	c->key_hash = key_r5_hash;
275 
276 	idx->ch.node_type = UBIFS_IDX_NODE;
277 	idx->child_cnt = cpu_to_le16(1);
278 	ino_key_init(c, &key, UBIFS_ROOT_INO);
279 	br = ubifs_idx_branch(c, idx, 0);
280 	key_write_idx(c, &key, &br->key);
281 	br->lnum = cpu_to_le32(main_first + DEFAULT_DATA_LEB);
282 	br->len  = cpu_to_le32(UBIFS_INO_NODE_SZ);
283 	err = ubifs_write_node(c, idx, tmp, main_first + DEFAULT_IDX_LEB, 0,
284 			       UBI_UNKNOWN);
285 	kfree(idx);
286 	if (err)
287 		return err;
288 
289 	dbg_gen("default root indexing node created LEB %d:0",
290 		main_first + DEFAULT_IDX_LEB);
291 
292 	/* Create default root inode */
293 	tmp = ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size);
294 	ino = kzalloc(tmp, GFP_KERNEL);
295 	if (!ino)
296 		return -ENOMEM;
297 
298 	ino_key_init_flash(c, &ino->key, UBIFS_ROOT_INO);
299 	ino->ch.node_type = UBIFS_INO_NODE;
300 	ino->creat_sqnum = cpu_to_le64(++c->max_sqnum);
301 	ino->nlink = cpu_to_le32(2);
302 	tmp_le64 = cpu_to_le64(CURRENT_TIME_SEC.tv_sec);
303 	ino->atime_sec   = tmp_le64;
304 	ino->ctime_sec   = tmp_le64;
305 	ino->mtime_sec   = tmp_le64;
306 	ino->atime_nsec  = 0;
307 	ino->ctime_nsec  = 0;
308 	ino->mtime_nsec  = 0;
309 	ino->mode = cpu_to_le32(S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO);
310 	ino->size = cpu_to_le64(UBIFS_INO_NODE_SZ);
311 
312 	/* Set compression enabled by default */
313 	ino->flags = cpu_to_le32(UBIFS_COMPR_FL);
314 
315 	err = ubifs_write_node(c, ino, UBIFS_INO_NODE_SZ,
316 			       main_first + DEFAULT_DATA_LEB, 0,
317 			       UBI_UNKNOWN);
318 	kfree(ino);
319 	if (err)
320 		return err;
321 
322 	dbg_gen("root inode created at LEB %d:0",
323 		main_first + DEFAULT_DATA_LEB);
324 
325 	/*
326 	 * The first node in the log has to be the commit start node. This is
327 	 * always the case during normal file-system operation. Write a fake
328 	 * commit start node to the log.
329 	 */
330 	tmp = ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size);
331 	cs = kzalloc(tmp, GFP_KERNEL);
332 	if (!cs)
333 		return -ENOMEM;
334 
335 	cs->ch.node_type = UBIFS_CS_NODE;
336 	err = ubifs_write_node(c, cs, UBIFS_CS_NODE_SZ, UBIFS_LOG_LNUM,
337 			       0, UBI_UNKNOWN);
338 	kfree(cs);
339 
340 	ubifs_msg("default file-system created");
341 	return 0;
342 }
343 
344 /**
345  * validate_sb - validate superblock node.
346  * @c: UBIFS file-system description object
347  * @sup: superblock node
348  *
349  * This function validates superblock node @sup. Since most of data was read
350  * from the superblock and stored in @c, the function validates fields in @c
351  * instead. Returns zero in case of success and %-EINVAL in case of validation
352  * failure.
353  */
354 static int validate_sb(struct ubifs_info *c, struct ubifs_sb_node *sup)
355 {
356 	long long max_bytes;
357 	int err = 1, min_leb_cnt;
358 
359 	if (!c->key_hash) {
360 		err = 2;
361 		goto failed;
362 	}
363 
364 	if (sup->key_fmt != UBIFS_SIMPLE_KEY_FMT) {
365 		err = 3;
366 		goto failed;
367 	}
368 
369 	if (le32_to_cpu(sup->min_io_size) != c->min_io_size) {
370 		ubifs_err("min. I/O unit mismatch: %d in superblock, %d real",
371 			  le32_to_cpu(sup->min_io_size), c->min_io_size);
372 		goto failed;
373 	}
374 
375 	if (le32_to_cpu(sup->leb_size) != c->leb_size) {
376 		ubifs_err("LEB size mismatch: %d in superblock, %d real",
377 			  le32_to_cpu(sup->leb_size), c->leb_size);
378 		goto failed;
379 	}
380 
381 	if (c->log_lebs < UBIFS_MIN_LOG_LEBS ||
382 	    c->lpt_lebs < UBIFS_MIN_LPT_LEBS ||
383 	    c->orph_lebs < UBIFS_MIN_ORPH_LEBS ||
384 	    c->main_lebs < UBIFS_MIN_MAIN_LEBS) {
385 		err = 4;
386 		goto failed;
387 	}
388 
389 	/*
390 	 * Calculate minimum allowed amount of main area LEBs. This is very
391 	 * similar to %UBIFS_MIN_LEB_CNT, but we take into account real what we
392 	 * have just read from the superblock.
393 	 */
394 	min_leb_cnt = UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs;
395 	min_leb_cnt += c->lpt_lebs + c->orph_lebs + c->jhead_cnt + 6;
396 
397 	if (c->leb_cnt < min_leb_cnt || c->leb_cnt > c->vi.size) {
398 		ubifs_err("bad LEB count: %d in superblock, %d on UBI volume, "
399 			  "%d minimum required", c->leb_cnt, c->vi.size,
400 			  min_leb_cnt);
401 		goto failed;
402 	}
403 
404 	if (c->max_leb_cnt < c->leb_cnt) {
405 		ubifs_err("max. LEB count %d less than LEB count %d",
406 			  c->max_leb_cnt, c->leb_cnt);
407 		goto failed;
408 	}
409 
410 	if (c->main_lebs < UBIFS_MIN_MAIN_LEBS) {
411 		err = 7;
412 		goto failed;
413 	}
414 
415 	if (c->max_bud_bytes < (long long)c->leb_size * UBIFS_MIN_BUD_LEBS ||
416 	    c->max_bud_bytes > (long long)c->leb_size * c->main_lebs) {
417 		err = 8;
418 		goto failed;
419 	}
420 
421 	if (c->jhead_cnt < NONDATA_JHEADS_CNT + 1 ||
422 	    c->jhead_cnt > NONDATA_JHEADS_CNT + UBIFS_MAX_JHEADS) {
423 		err = 9;
424 		goto failed;
425 	}
426 
427 	if (c->fanout < UBIFS_MIN_FANOUT ||
428 	    ubifs_idx_node_sz(c, c->fanout) > c->leb_size) {
429 		err = 10;
430 		goto failed;
431 	}
432 
433 	if (c->lsave_cnt < 0 || (c->lsave_cnt > DEFAULT_LSAVE_CNT &&
434 	    c->lsave_cnt > c->max_leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS -
435 	    c->log_lebs - c->lpt_lebs - c->orph_lebs)) {
436 		err = 11;
437 		goto failed;
438 	}
439 
440 	if (UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs + c->lpt_lebs +
441 	    c->orph_lebs + c->main_lebs != c->leb_cnt) {
442 		err = 12;
443 		goto failed;
444 	}
445 
446 	if (c->default_compr < 0 || c->default_compr >= UBIFS_COMPR_TYPES_CNT) {
447 		err = 13;
448 		goto failed;
449 	}
450 
451 	max_bytes = c->main_lebs * (long long)c->leb_size;
452 	if (c->rp_size < 0 || max_bytes < c->rp_size) {
453 		err = 14;
454 		goto failed;
455 	}
456 
457 	if (le32_to_cpu(sup->time_gran) > 1000000000 ||
458 	    le32_to_cpu(sup->time_gran) < 1) {
459 		err = 15;
460 		goto failed;
461 	}
462 
463 	return 0;
464 
465 failed:
466 	ubifs_err("bad superblock, error %d", err);
467 	dbg_dump_node(c, sup);
468 	return -EINVAL;
469 }
470 
471 /**
472  * ubifs_read_sb_node - read superblock node.
473  * @c: UBIFS file-system description object
474  *
475  * This function returns a pointer to the superblock node or a negative error
476  * code.
477  */
478 struct ubifs_sb_node *ubifs_read_sb_node(struct ubifs_info *c)
479 {
480 	struct ubifs_sb_node *sup;
481 	int err;
482 
483 	sup = kmalloc(ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size), GFP_NOFS);
484 	if (!sup)
485 		return ERR_PTR(-ENOMEM);
486 
487 	err = ubifs_read_node(c, sup, UBIFS_SB_NODE, UBIFS_SB_NODE_SZ,
488 			      UBIFS_SB_LNUM, 0);
489 	if (err) {
490 		kfree(sup);
491 		return ERR_PTR(err);
492 	}
493 
494 	return sup;
495 }
496 
497 /**
498  * ubifs_write_sb_node - write superblock node.
499  * @c: UBIFS file-system description object
500  * @sup: superblock node read with 'ubifs_read_sb_node()'
501  *
502  * This function returns %0 on success and a negative error code on failure.
503  */
504 int ubifs_write_sb_node(struct ubifs_info *c, struct ubifs_sb_node *sup)
505 {
506 	int len = ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size);
507 
508 	ubifs_prepare_node(c, sup, UBIFS_SB_NODE_SZ, 1);
509 	return ubifs_leb_change(c, UBIFS_SB_LNUM, sup, len, UBI_LONGTERM);
510 }
511 
512 /**
513  * ubifs_read_superblock - read superblock.
514  * @c: UBIFS file-system description object
515  *
516  * This function finds, reads and checks the superblock. If an empty UBI volume
517  * is being mounted, this function creates default superblock. Returns zero in
518  * case of success, and a negative error code in case of failure.
519  */
520 int ubifs_read_superblock(struct ubifs_info *c)
521 {
522 	int err, sup_flags;
523 	struct ubifs_sb_node *sup;
524 
525 	if (c->empty) {
526 		err = create_default_filesystem(c);
527 		if (err)
528 			return err;
529 	}
530 
531 	sup = ubifs_read_sb_node(c);
532 	if (IS_ERR(sup))
533 		return PTR_ERR(sup);
534 
535 	/*
536 	 * The software supports all previous versions but not future versions,
537 	 * due to the unavailability of time-travelling equipment.
538 	 */
539 	c->fmt_version = le32_to_cpu(sup->fmt_version);
540 	if (c->fmt_version > UBIFS_FORMAT_VERSION) {
541 		ubifs_err("on-flash format version is %d, but software only "
542 			  "supports up to version %d", c->fmt_version,
543 			  UBIFS_FORMAT_VERSION);
544 		err = -EINVAL;
545 		goto out;
546 	}
547 
548 	if (c->fmt_version < 3) {
549 		ubifs_err("on-flash format version %d is not supported",
550 			  c->fmt_version);
551 		err = -EINVAL;
552 		goto out;
553 	}
554 
555 	switch (sup->key_hash) {
556 	case UBIFS_KEY_HASH_R5:
557 		c->key_hash = key_r5_hash;
558 		c->key_hash_type = UBIFS_KEY_HASH_R5;
559 		break;
560 
561 	case UBIFS_KEY_HASH_TEST:
562 		c->key_hash = key_test_hash;
563 		c->key_hash_type = UBIFS_KEY_HASH_TEST;
564 		break;
565 	};
566 
567 	c->key_fmt = sup->key_fmt;
568 
569 	switch (c->key_fmt) {
570 	case UBIFS_SIMPLE_KEY_FMT:
571 		c->key_len = UBIFS_SK_LEN;
572 		break;
573 	default:
574 		ubifs_err("unsupported key format");
575 		err = -EINVAL;
576 		goto out;
577 	}
578 
579 	c->leb_cnt       = le32_to_cpu(sup->leb_cnt);
580 	c->max_leb_cnt   = le32_to_cpu(sup->max_leb_cnt);
581 	c->max_bud_bytes = le64_to_cpu(sup->max_bud_bytes);
582 	c->log_lebs      = le32_to_cpu(sup->log_lebs);
583 	c->lpt_lebs      = le32_to_cpu(sup->lpt_lebs);
584 	c->orph_lebs     = le32_to_cpu(sup->orph_lebs);
585 	c->jhead_cnt     = le32_to_cpu(sup->jhead_cnt) + NONDATA_JHEADS_CNT;
586 	c->fanout        = le32_to_cpu(sup->fanout);
587 	c->lsave_cnt     = le32_to_cpu(sup->lsave_cnt);
588 	c->rp_size       = le64_to_cpu(sup->rp_size);
589 	c->rp_uid        = le32_to_cpu(sup->rp_uid);
590 	c->rp_gid        = le32_to_cpu(sup->rp_gid);
591 	sup_flags        = le32_to_cpu(sup->flags);
592 	if (!c->mount_opts.override_compr)
593 		c->default_compr = le16_to_cpu(sup->default_compr);
594 
595 	c->vfs_sb->s_time_gran = le32_to_cpu(sup->time_gran);
596 	memcpy(&c->uuid, &sup->uuid, 16);
597 	c->big_lpt = !!(sup_flags & UBIFS_FLG_BIGLPT);
598 
599 	/* Automatically increase file system size to the maximum size */
600 	c->old_leb_cnt = c->leb_cnt;
601 	if (c->leb_cnt < c->vi.size && c->leb_cnt < c->max_leb_cnt) {
602 		c->leb_cnt = min_t(int, c->max_leb_cnt, c->vi.size);
603 		if (c->vfs_sb->s_flags & MS_RDONLY)
604 			dbg_mnt("Auto resizing (ro) from %d LEBs to %d LEBs",
605 				c->old_leb_cnt,	c->leb_cnt);
606 		else {
607 			dbg_mnt("Auto resizing (sb) from %d LEBs to %d LEBs",
608 				c->old_leb_cnt, c->leb_cnt);
609 			sup->leb_cnt = cpu_to_le32(c->leb_cnt);
610 			err = ubifs_write_sb_node(c, sup);
611 			if (err)
612 				goto out;
613 			c->old_leb_cnt = c->leb_cnt;
614 		}
615 	}
616 
617 	c->log_bytes = (long long)c->log_lebs * c->leb_size;
618 	c->log_last = UBIFS_LOG_LNUM + c->log_lebs - 1;
619 	c->lpt_first = UBIFS_LOG_LNUM + c->log_lebs;
620 	c->lpt_last = c->lpt_first + c->lpt_lebs - 1;
621 	c->orph_first = c->lpt_last + 1;
622 	c->orph_last = c->orph_first + c->orph_lebs - 1;
623 	c->main_lebs = c->leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS;
624 	c->main_lebs -= c->log_lebs + c->lpt_lebs + c->orph_lebs;
625 	c->main_first = c->leb_cnt - c->main_lebs;
626 	c->report_rp_size = ubifs_reported_space(c, c->rp_size);
627 
628 	err = validate_sb(c, sup);
629 out:
630 	kfree(sup);
631 	return err;
632 }
633